There is a need for potable water in all areas of the world. In developed countries, water is purified and potable water is supplied on a large scale, typically by large national or multinational water management companies. This water is typically supplied directly to the consumers homes in a potable form. However, in some parts of the world, for example in some rural areas of developing countries, many people either do not have a direct water supply to their homes and only have access to a non-potable communal water supply such as a village well, or cannot be guaranteed that the water they do receive is potable. As a result, considerable numbers of people die each year as the direct result of drinking contaminated drinking water. Thus, there is a need for water purification kits and compositions that allow the consumer to purify their own water, which produces potable water in a fast and efficient manner.
Current water purification compositions available on the market to date, consist mainly of disinfectants, e.g. sources of chlorine and/or iodine, and do not adequately purify water. Water which is obtained after treatment by these water purification kits, may still comprise amounts of water impurities, e.g. heavy metal ions such as arsenic, which, when continually consumed for a prolonged period of time, may lead to health problems. Thus, there is a need to provide a water purification composition which removes water-impurities like heavy metal ions including arsenic and lead, more efficiently and effectively than current water purification kits.
It has now been found that water purification compositions based on certain combinations of inorganic coagulants and water-soluble or water-dispersible polymers remove greater amounts of water impurities, such as heavy metals, from water compared to current water purification compositions.
Also, current water purification compositions do not adequately remove, kill or inactive micro-organisms such as bacteria, viruses and cysts, which are present in the water. Thus, there remains a need to provide a water purification composition which does adequately remove, kill or inactive these micro-organisms.
It has now been found that when the composition of the present invention comprises a disinfecting agent, the composition removes, kills or inactivates a surprisingly larger amount of micro-organisms such as bacteria, viruses and cysts compared to water purification compositions known in the art.
In addition, the water which is to be purified by a water purification composition typically comprises a large amount of water-soluble organic content such as humic acid. With current water purification compositions, bleach, especially chlorine based bleach, can react with the water-soluble organic content and produce by-products in the water, including chlorine derivatives such as chloroacetic acid or chloroform, which are harmful to human and animal health. Thus, there is a need to provide water purification compositions, methods and kits which produce purified water comprising a low amount of disinfection by-products.
Another problem associated with the use of certain chlorine-based disinfectants such as calcium hypochlorite is that of product stability. In particular, it has been found that known compositions based on calcium hypochlorite can lose substantial disinfection efficacy under regular conditions of storage and use. Thus, there is a need for purification and disinfection compositions having improved storage stability.
After purification and disinfection of contaminated drinking water, there raises the further problem of maintaining the purity and aesthetic quality of the water until such time as it is required for drinking, whilst at the same time providing drinking water of satisfactory taste. In this context, it has been found that the use of chlorine-based disinfectants and coagulants for treating drinking water containing high levels of soluble manganese contamination, introduced either from the water or from the coagulant itself, can lead to the onset of a water discoloration effect subsequent to the flocculation step. Such a discolouration effect is referred to herein as ‘manganese-associated post-flocculation discoloration’ of the drinking water. Although the reasons for this effect are not fully understood, it is believed that residual soluble manganese remaining after the coagulation and flocculation reaction has taken place is prone to oxidation by chlorine-based disinfectant with the formation of highly colored pure or mixed colloidal species that contain some manganese dioxide. Thus there is a need for compositions, methods and kits for purifying contaminated drinking water and which provides purified water having improved aesthetics as well as longer life and improved taste attributes.
In addition to the need for purifying and clarifying contaminated drinking water, there is also a huge need in many parts of the world to improve standards of nutrition and health. The effective provision of both clean water and essential minerals and vitamins would clearly be of universal benefit but especially so in those parts of the world where potable water is in short supply. Thus there is a need for compositions, methods and kits for purifying and at the same time nutrifying contaminated drinking water.